Suppression of metal catalysis



sales SEESSION 0F 111 TAL CATYSKS Joseph Univ oil cts a W $1031 of all i i 3.: a

Chenicek. Chicago. nil.

Company, Chi l No Drawing. Application spin 8, 1940, Serial No. teams as s. (01. 4%73) This inventionrelates to a. method for sup pressing deterioration of olefin-containing hydrocarbon distillates such as results from the catakeep the motor fuel in satisfactory condition for use in internal combustion engines. They tend to prevent losses in antiknock value which accompanies,oxidation of this type of gasoline. Among the materials which have been used are various phenolic and amino compounds as well as trace tions of wood tar oil particularly from hardwood tars boiling in the range of about 240-280 0., etc., which are usually added to the gasoline in concentrations of approximately (mill-0.1%, depending upon the efiectiveness of the particular compound used and the gasoline to which it is added.

Although inhibitors are used in both treated and untreated gasolines, it is with the latter type that they find the greatest application. Treated gasolines are those-which have been subjected to chemical refining procemes such as sulfuric acid. iullers earth, and the like, either with or without a sweetening treatment following. Untreated gasoiines are those which have received no refinement beyond possibly caustic washing and/or sweetening. The former type of gasoline is usually relatively stable and requires little or no added inhibitor. although" the use of inhibitors has been practiced to supplement other refining methods. In the case of untreated gasolines, on the other hand, many of them are unstable and require the protection afforded by inhibitors to prevent undue deterioration during the time they are in storage.

Practically all gasolines require some form of sweetening treatment in order to improve the odor thereof and produce '5 product having a negative doctor test. The sodium plumbite or doctor process, as well as the hypochlorite sweetenlng process, have been used in the past with considerable success. During recent years. he

so-called copper sweetening process has been developed in which gasoline is contacted with a copper-containing reagent. As a result of the presence of relatively minor amounts of impurities in such gasolines, the sweetened gasoline usually contains relatively small amounts of copper compounds which have a catalytic effect on oxidation reactions which may result when the gasoline comes in contact with air. various methods have been developed for removing such copper compounds incl treatment with alkali or alkaline earth metal sulfides, and heavy metal sulfides such as zinc sulfide and the like. In some instances, however, these reagents may not be completely efiectivein removing the copper from the gasoline and as a consequence the gasoline may have a reduced stability and susceptibility to added gasoline gum inhibitors. Moreover, gasolines come in contact with various metals in the course of refining, storing and shipping operations, and this may result in the gasoline containing minute amounts of such metals as copper. iron, cobalt, nickel and the line which are oxidation catalysts. It is with a method oi preventing depreciation due to the presence of such catalysts that this invention is concerned.

In one specific embodiment the present invention comprises a method for. suppressing the catalytic action of metal compounds which may be contained in hydrocarbon distillates such as gasolines, and which tend to promote theformation of gum therein by adding to said gasoline approximately 0.0001-0.0l %-of a condensation product 01' an orthohydroxy aromatic aldehyde and a primary alkyl amine either with or without a gasoline gum inhibitor.

Compounds of this type may be represented by the general formula:

wherein R is a substituent group such as hydrogen, aikyLaryl. hydroq'l, halogen, nitro, al-. koxy,. aryloxy orf-aminorgroup, and .R' is an Typical examples of this type of alkylgroup.

compound are orthohydroxy benzaldehyde ess if any given stock. The proper choice of a uppresser for any particular oil will depend .pon these factors and is, in the end, a matter f test.

In some cases the compounds may be used in he gasoline without added gum inhibitors. This a particularly true when used in connection with traight-run distillates or cracked gasolines lhich have been refined toan adequate degree f stability such as by acid-treatment or other uitable methods. However, these compounds .re not of themselves gasoline gum inhibitors :xcept to a minor extent, so that they do not esult in a gasoline of improved stability except when metal compounds are present therein.

However, the usual method of application is add both the suppresser and the gasoline gum nhibitor simultaneously. The resulting inducion period is usually the same or slightly in- :reased over that obtainable with the inhibitor done in a gasoline free of metal compounds. the suppresser may be dissolved in the gasoline um inhibitor. As a rule, smaller amounts of ;he suppresser are required than of the gum nhibitor, so that a relatively minor amount oi :he suppresser may be added to the inhibitor,

say for example, less than 50% of the total nixture.

The following example is given to illustrate the usefulness of the invention, but should not be construed as limiting it to the compounds- ;hown therein.

A cracked Pennsylvania gasoline which had been copper-sweetened was found to contain 1 mg. of copper/liter of gasoline. The induction period by the oxygen bomb method was 40 minutes. Upon the addition of N-butyl aminophenol, the induction period was increased to 85 minutes. Representative compounds of this invention were added to the inhibited gasoline with the following results. When adding 0.01% or orthohydroxy benzaldehyde ethylimine, the induction period was 270 minutes, with orthohydroxy benzaldehyde butylimine the induction period was 220 minutes, with orthohydroxy benzaldehyde octyl-imine the induction period was 170 minutes, and the 2-hydroxy-1-naphthaldehyde butylimine the induction period was 255 minutes.

I claim as my invention:

1. A process for suppressing the catalytic effect of metal compounds on hydrocarbon distillate which comprises adding to said distillate a relatively minor portion of a metal-free condensation product of an orthohydroxy aromatic aldehyde and a primary alkane mono-amine.

2. A process for suppressing the catalytic effect of metal compounds on gum formation in olefine-containing hydrocarbon distillate which comprises adding to said distillate a relatively minor portion of a metal-free condensation product of an orthohydroxy aromatic aldehyde and a primary alkane mono-amine.

3. A process for suppressing the catalytic effect of metal compounds on gum formation in cracked gasoline which comprises adding to said gasoline a relatively minor portion of a metalfree condensation product of an orthohydroxy benzaldehyde and a primary alkane mono-amine.

4. A process for suppressing the catalytic effect of metal compounds. on cracked gasoline which comprises adding to said gasoline a gum inhibitor and a metal-free condensation product of an orthohydroxy aromatic aldehyde and a primary alkane mono-amine.

5. A process for suppressing the catalytic effect of metal compounds on cracked gasoline which comprises adding thereto a metal-free condensation product of an orthohydroxy mono-nuclear aromatic aldehyde and a primary alkane mono-amine.

6. A process for suppressing the catalytic ei-.

fect of metal compounds on cracked gasoline which comprises adding thereto a metal-free condensation product of an orthohydroxy polynuclear aromatic aldehyde and a primary alkane -mono-amine.

'7. A process fOr suppressing the catalytic effect of metal compounds on cracked gasoline which comprises adding thereto an N-substituted alkyl aminophenol and a metal-free condensation product of an orthohydroxy aromatic aldehyde with a primary alkane mono-amine.

8. A process for suppressing the catalytic efiect of metal compounds on cracked gasoline which comprises adding thereto a wood tar distillate gasoline gum inhibitor boiling within the range of approximately 240-280 C. and a metal-free condensation product of an orthohydroxy aromatic aldehyde with a primary alkane monoamine.

9. A process for suppressing the catalytic effect of metal compounds on hydrocarbon distillate which comprises adding thereto 2-hydroxy-1- naphthaldehyde butylimine.

10. A process for suppressing the catalytic effect of metal compounds on cracked gasoline which comprises adding thereto a metal-free condensation product of an orthohydroxy benzaldehyde and a primary alkane mono-amine in an amount within the limits of approximately 11. A process for suppressing the catalytic effect of metal compounds on olefin-containing hydrocarbon distillate which comprises addin thereto a metal-tree compound whose general formula includes the structure:

wherein R is an alkane group.

12. A process for suppressing the catalytic effect of metal compounds on olefin-containing hydrocarbon distillate which comprises adding thereto a metal-free compound whose general formula includes the structure:

aseaeea ing metal compounds comprising essentially a mixture of a guru inhibitor with a metal-free condensation product of an orthohydroxy mononuclear aromatic aldehyde with a primary alkane mono-amine. v

15. An inhibitor for cracked gasoline containing metal compounds comprising essentially a mixture of a gasoline gum inhibitor with a metalfree condensation product of an orthohydroxy poly-nuclear aromatic aldehyde and a primary traces of metallic compounds catalytically active to accelerate oxidation comprising adding thereto a small quantity of suppresser compound having the formula where R is alkyl. I

19. Method of stabilizing gasoline containing traces oi. metallic compounds cataiytically active to accelerate oxidation comprising adding thereto a small amount of a hydroxy aromatic compound containing the radial CH=NR directly attached to the aromatic ring and in which R. is an allwl group, the hydroiw group of the aromatic nucleus being in the ortho position with respect to said radical.

20. Motor fuel comprising oleflnic gasoline containing metallic compounds catalytically active to accelerate oxidation, and a relatively small amount of a metal-free hydroxy aromatic compound containing the radical C =-NR directly attached to the aromatic ring and in which R is an alkyl group. the hydrow group of the arcmatic nucleus being in the ortho position with respect to said radical.

21. Motor fuel comprising oleiinic gasoline containing metallic compounds catalyticaliy active to accelerate oxidation, and a relatively small amount 01' a metal-free condensation product of 20 an orthohydroxy aromatic aldehyde and a primary alkane'mono-amine.

, 22. Motor fuel comprising oleflnic gasoline containing metallic compounds catalyticaliy active to accelerate oxidation and relatively small 25 amounts of a gum inhibitor and a metal-free hydroxy aromatic compound containing the radical CH NR directly attached to the aromatic ring and in which R is an alkyl group, the hydroxy group of the aromatic nucleus being in the so. ortho position with respect to said radical.

23. Motor fuel comprising oleflnic gasoline containing metallic compounds catalytically active to accelerate oxidation, and relatively small amounts of a gum inhibitor and a metal-free con- 5 densation product of a-orthohydroxy aromatic aldehyde and a primary allrane mono-amine. JOSEPH A. CHENICEK. 

